1. Technical Field
The presently disclosed subject matter relates to a light emitting apparatus, and in particular, a reverse surface mount type LED apparatus.
2. Description of the Related Art
FIG. 1 shows a cross sectional view showing the configuration of a conventional surface mount LED apparatus (see, for example, Japanese Utility Model Application Laid-Open No. Sho. 64-6038), which is mounted in a reverse surface mount fashion. With reference to FIG. 1, the reverse surface mount LED apparatus 91 is mounted on a lower surface of a mounting board 911 having a hole 912 formed therethrough (in a reverse surface mount fashion) so as to project light through the hole 912 of the mounting board 911. The reverse surface mount LED apparatus 91 shown in FIG. 1 does not protrude over the upper surface of the mounting board 911 toward the illumination direction when compared to those mounted on the upper surface of a mounting board. Accordingly, this reverse surface mount type LED apparatus can contribute to the low-profile products, and can be applied to, for example, reverse surface mount type custom LED tail lamps (CTL) or the like.
Specifically, the reverse surface mount type LED apparatus 91 of FIG. 1 can include: a base 92, a first patterned electrode 93a and a second patterned electrode 93b extending from the upper surface of the base 92 to the rear surface thereof; an abutment plate 94 for receiving a mounter; a light emitting device (or an LED device) 96 mounted on the first patterned electrode 93a on the upper side of the base 92; a wiring 97 (a bonding wiring) 97 connecting the light emitting device 96 to the second patterned electrode 93b; and a resin portion 98 formed on the upper side of the base 92 for covering the light emitting device 96, the wiring 97, and the like.
The reverse surface mount LED apparatus 91 configured as above can be mounted as follows: A soldering paste is applied onto soldering lands 913 provided on both sides of the hole 912 of the mounting board 911 via a mask or the like; the LED apparatus 91 is mounted on the mounting board 911 by applying a load to the apparatus 91 by means of a mounter (see FIG. 2); and the soldering paste is melted by reflowing process or the like process and then solidified to fix the LED apparatus 91.
As described above, a mounter 920, an example of which is shown in FIG. 2, is used for mounting a reverse surface mount type LED apparatus 91 on a mounting board 911. Some types of such a mounter cannot control the application of load during mounting operation. In some cases, as shown in FIG. 3, an excessive load can be applied to the reverse surface mount type LED apparatus 91. In particular, the pressure force may be concentrated at the center area of the reverse surface mount type LED apparatus 91 because the hole 912 is formed in the mounting board 911 correspondingly. In a preferred case, the pressure force can be dispersed over the entire body of the reverse surface mount type LED apparatus 91 including the resin portion 98. However, the thick resin portion 8 may be stronger than the other parts, resulting in being stiff (not flexible). As a result, when a stress is concentrated around the center area of the reverse surface mount type LED apparatus 91, deformation may occur around the boundary of the resin portion 98. Although the resin portion 98 is adhered to the base 92, when the stress is applied therearound, the resin portion 98 may be partly exfoliated from the base 92 around the portion as shown by the reference symbol A in FIG. 3. When the resin portion 98 is exfoliated from the base 92, the LED device 96, the bonding wiring 97, and the like covered by the resin portion 98 may also be lifted up from the base 92. This may cause the electrical connection failure, resulting in the lighting failure after completion of the mounting operation.